Optimization of an Internal Patch Antenna of a Mobile Phone

Model

In this project, the internal patch antenna of the modified generic phone will be build as a parameterized object and then will be optimized to operate at 900MHz (see the top picture). The antenna is basically a shorted patch which represents typical modern internal mobile phone antenna. Thus the optimization problem presented here has real practical applications. The optimization goal is to obtain the return loss better than -10 dB at 900MHz with a bandwidth of 50MHz. The dimensions of the slots and their positions are the parameters to be optimized to obtain a successful design.

Simulation

The template simulation is initially prepared. The optimization module uses the template project model and settings during optimization process. The windows appears with the module guides the user to set the optimization method, variables step-by-step and to start the optimization. Optimization Running window will appear enabling the user to start the optimization, visualize the fitness after each simulation and the best achieved S-parameter performance. The optimization algorithm sets the variables according to the settings and SEMCAD X automatically performs the changes in the model accordingly. Then the grid and voxels are generated and finally the first simulation starts. The geometry of the project currently running can be visualized on the SEMCAD X modeling window. The second figure illustrates typical optimization run with simulation, optimization and modeling windows.

Results

The optimization process ends if either the maximum number of iterations or the optimization goal is achieved. In both cases, the SEMCAD X project having the best fitness value can be found in the same folder as the template simulation. The return loss of the patch antenna before and after the optimization is shown in the bottom figure which clearly demonstrates the improvement of the response in the frequency range of interest.